1. Field of the Invention
The present invention relates to power supply systems and more particularly, to a power supplying and data transmitting method used in an induction type power supply system consisting of a power supply module and a power-receiving module for transmission of electrical energy and data signal.
2. Description of the Related Art
With the coming of digital era, many digitalized electronic products, such as digital camera, cellular telephone, music player (MP3, MP4) and etc., have been continuously developed and have appeared on the market. These modern digital electronic products commonly have light, thin, short and small characteristics. For high mobility, power supply is an important factor. A mobile digital electronic product generally uses a rechargeable battery to provide the necessary working voltage. When power low, the rechargeable battery can be recharged. For charging the rechargeable battery of a digital electronic product, a battery charger shall be used. However, it is not economic to purchase a respective battery charger when buying a new mobile electronic product.
Further, when using a battery charger to charge the rechargeable battery of a mobile electronic product, it is necessary to connect the connection interface of the battery charger to an electric outlet and then insert the power output plug of the battery charger to the power jack of the mobile electronic product. After charging, the user needs to remove the battery charger from the mobile electronic product. When wishing to charge the rechargeable battery of a mobile electronic product, the user must carry the mobile electronic product to a place where there is an electric outlet. When one goes out and there is no any electric outlet available, the user will be unable to charge the rechargeable battery of his (her) mobile electronic product.
Further, except of charging the battery, an electronic device may have to make certain function settings, to edit data, or to transmit data. Some electronic devices allow the use make setting and to edit and transmit data. However, some other electronic devices (such as, MP3, MP4, digital camera, electronic watch, portable game machine, wireless game grip, remote controller, and etc.) do not allow direct setting, data editing or data transmission. In this case, an external electronic device (computer, PDA) must be used to achieve setting, data editing or data transmission. Further, an electronic device cannot be operated to transmit data during battery charging.
Taiwan Patent Publication No. 201004086 discloses a power supply system, entitled “Induction type power supply system with battery scan function”, filed on Feb. 20, 2009 under application serial number 98105373, and issued on Jan. 16, 2010. This invention teaches the use of a load resistor for a signal modulation in an induction type power supply system to feed back signal from the secondary coil to the primary coil. However, this method still has drawbacks as follows:
1. The resistor type modulator consumes much power during signal modulation. The dynamic range of the modulation is determined subject to the value of the resistance at the load. Because the signal analysis ability of the primary coil in the power supply system is reduced subject to increasing of the distance of the secondary coil, the modulation dynamic range must be enhanced for data analysis, i.e., the resistance value must be reduced to amplify load effect during modulation. However, this method has a limitation. When the resistance at the load is close to a short-circuit status, no further adjustment is allowed.
2. During modulation, the positive pole of the power supply at the power-receiving end approaches the ground terminal. At this time, a surge goes through the rectifier and the voltage stabilizer in the loop, causing a sudden rise of temperature that may damage circuit components.
3. Due to the limitation of electrical characteristics, the resistor load must be installed posterior to the rectifier with a filter capacitor bridged over the ends. This voltage stabilizing effect slows down signal modulation reaction speed. In consequence, a relatively higher carrier frequency is necessary for signal analysis.
4. The transmission of signal is a one-way transmission to transmit the feedback signal from the secondary coil to the primary coil, i.e., the method does not allow transmission of a signal from the primary coil to the secondary coil.
Therefore, it is desirable to a power supplying and data transmitting method for induction type power supply system that eliminates the aforesaid problems.